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[PULL 21/22] qcow2: Convert qcow2_alloc_cluster_offset() into qcow2_allo
From: |
Max Reitz |
Subject: |
[PULL 21/22] qcow2: Convert qcow2_alloc_cluster_offset() into qcow2_alloc_host_offset() |
Date: |
Tue, 15 Sep 2020 12:46:26 +0200 |
From: Alberto Garcia <berto@igalia.com>
qcow2_alloc_cluster_offset() takes an (unaligned) guest offset and
returns the (aligned) offset of the corresponding cluster in the qcow2
image.
In practice none of the callers need to know where the cluster starts
so this patch makes the function calculate and return the final host
offset directly. The function is also renamed accordingly.
See 388e581615 for a similar change to qcow2_get_cluster_offset().
Signed-off-by: Alberto Garcia <berto@igalia.com>
Message-Id:
<9bfef50ec9200d752413be4fc2aeb22a28378817.1599833007.git.berto@igalia.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
---
block/qcow2.h | 6 +++---
block/qcow2-cluster.c | 14 ++++++++++----
block/qcow2.c | 36 +++++++++++++-----------------------
3 files changed, 26 insertions(+), 30 deletions(-)
diff --git a/block/qcow2.h b/block/qcow2.h
index b73a4cf1f8..b71e444fca 100644
--- a/block/qcow2.h
+++ b/block/qcow2.h
@@ -901,9 +901,9 @@ int qcow2_encrypt_sectors(BDRVQcow2State *s, int64_t
sector_num,
int qcow2_get_host_offset(BlockDriverState *bs, uint64_t offset,
unsigned int *bytes, uint64_t *host_offset,
QCow2SubclusterType *subcluster_type);
-int qcow2_alloc_cluster_offset(BlockDriverState *bs, uint64_t offset,
- unsigned int *bytes, uint64_t *host_offset,
- QCowL2Meta **m);
+int qcow2_alloc_host_offset(BlockDriverState *bs, uint64_t offset,
+ unsigned int *bytes, uint64_t *host_offset,
+ QCowL2Meta **m);
int qcow2_alloc_compressed_cluster_offset(BlockDriverState *bs,
uint64_t offset,
int compressed_size,
diff --git a/block/qcow2-cluster.c b/block/qcow2-cluster.c
index 1a67b2d928..9acc6ce4ae 100644
--- a/block/qcow2-cluster.c
+++ b/block/qcow2-cluster.c
@@ -1719,6 +1719,10 @@ out:
* clusters (or subclusters) if necessary. The result can span a
* combination of allocated and previously unallocated clusters.
*
+ * Note that offset may not be cluster aligned. In this case, the returned
+ * *host_offset points to exact byte referenced by offset and therefore
+ * isn't cluster aligned as well.
+ *
* On return, @host_offset is set to the beginning of the requested
* area. This area is guaranteed to be contiguous on the qcow2 file
* but it can be smaller than initially requested. In this case @bytes
@@ -1736,9 +1740,9 @@ out:
*
* Return 0 on success and -errno in error cases
*/
-int qcow2_alloc_cluster_offset(BlockDriverState *bs, uint64_t offset,
- unsigned int *bytes, uint64_t *host_offset,
- QCowL2Meta **m)
+int qcow2_alloc_host_offset(BlockDriverState *bs, uint64_t offset,
+ unsigned int *bytes, uint64_t *host_offset,
+ QCowL2Meta **m)
{
BDRVQcow2State *s = bs->opaque;
uint64_t start, remaining;
@@ -1759,7 +1763,7 @@ again:
while (true) {
if (*host_offset == INV_OFFSET && cluster_offset != INV_OFFSET) {
- *host_offset = start_of_cluster(s, cluster_offset);
+ *host_offset = cluster_offset;
}
assert(remaining >= cur_bytes);
@@ -1842,6 +1846,8 @@ again:
*bytes -= remaining;
assert(*bytes > 0);
assert(*host_offset != INV_OFFSET);
+ assert(offset_into_cluster(s, *host_offset) ==
+ offset_into_cluster(s, offset));
return 0;
}
diff --git a/block/qcow2.c b/block/qcow2.c
index 1cb5daf39a..b05512718c 100644
--- a/block/qcow2.c
+++ b/block/qcow2.c
@@ -2559,7 +2559,7 @@ static coroutine_fn int qcow2_co_pwritev_part(
int offset_in_cluster;
int ret;
unsigned int cur_bytes; /* number of sectors in current iteration */
- uint64_t cluster_offset;
+ uint64_t host_offset;
QCowL2Meta *l2meta = NULL;
AioTaskPool *aio = NULL;
@@ -2580,16 +2580,13 @@ static coroutine_fn int qcow2_co_pwritev_part(
qemu_co_mutex_lock(&s->lock);
- ret = qcow2_alloc_cluster_offset(bs, offset, &cur_bytes,
- &cluster_offset, &l2meta);
+ ret = qcow2_alloc_host_offset(bs, offset, &cur_bytes,
+ &host_offset, &l2meta);
if (ret < 0) {
goto out_locked;
}
- assert(offset_into_cluster(s, cluster_offset) == 0);
-
- ret = qcow2_pre_write_overlap_check(bs, 0,
- cluster_offset + offset_in_cluster,
+ ret = qcow2_pre_write_overlap_check(bs, 0, host_offset,
cur_bytes, true);
if (ret < 0) {
goto out_locked;
@@ -2601,7 +2598,7 @@ static coroutine_fn int qcow2_co_pwritev_part(
aio = aio_task_pool_new(QCOW2_MAX_WORKERS);
}
ret = qcow2_add_task(bs, aio, qcow2_co_pwritev_task_entry, 0,
- cluster_offset + offset_in_cluster, offset,
+ host_offset, offset,
cur_bytes, qiov, qiov_offset, l2meta);
l2meta = NULL; /* l2meta is consumed by qcow2_co_pwritev_task() */
if (ret < 0) {
@@ -3129,13 +3126,12 @@ static int coroutine_fn preallocate_co(BlockDriverState
*bs, uint64_t offset,
while (bytes) {
cur_bytes = MIN(bytes, QEMU_ALIGN_DOWN(INT_MAX, s->cluster_size));
- ret = qcow2_alloc_cluster_offset(bs, offset, &cur_bytes,
- &host_offset, &meta);
+ ret = qcow2_alloc_host_offset(bs, offset, &cur_bytes,
+ &host_offset, &meta);
if (ret < 0) {
error_setg_errno(errp, -ret, "Allocating clusters failed");
goto out;
}
- host_offset += offset_into_cluster(s, offset);
for (m = meta; m != NULL; m = m->next) {
m->prealloc = true;
@@ -4043,10 +4039,9 @@ qcow2_co_copy_range_to(BlockDriverState *bs,
BdrvRequestFlags write_flags)
{
BDRVQcow2State *s = bs->opaque;
- int offset_in_cluster;
int ret;
unsigned int cur_bytes; /* number of sectors in current iteration */
- uint64_t cluster_offset;
+ uint64_t host_offset;
QCowL2Meta *l2meta = NULL;
assert(!bs->encrypted);
@@ -4057,31 +4052,26 @@ qcow2_co_copy_range_to(BlockDriverState *bs,
l2meta = NULL;
- offset_in_cluster = offset_into_cluster(s, dst_offset);
cur_bytes = MIN(bytes, INT_MAX);
/* TODO:
* If src->bs == dst->bs, we could simply copy by incrementing
* the refcnt, without copying user data.
* Or if src->bs == dst->bs->backing->bs, we could copy by discarding.
*/
- ret = qcow2_alloc_cluster_offset(bs, dst_offset, &cur_bytes,
- &cluster_offset, &l2meta);
+ ret = qcow2_alloc_host_offset(bs, dst_offset, &cur_bytes,
+ &host_offset, &l2meta);
if (ret < 0) {
goto fail;
}
- assert(offset_into_cluster(s, cluster_offset) == 0);
-
- ret = qcow2_pre_write_overlap_check(bs, 0,
- cluster_offset + offset_in_cluster, cur_bytes, true);
+ ret = qcow2_pre_write_overlap_check(bs, 0, host_offset, cur_bytes,
+ true);
if (ret < 0) {
goto fail;
}
qemu_co_mutex_unlock(&s->lock);
- ret = bdrv_co_copy_range_to(src, src_offset,
- s->data_file,
- cluster_offset + offset_in_cluster,
+ ret = bdrv_co_copy_range_to(src, src_offset, s->data_file, host_offset,
cur_bytes, read_flags, write_flags);
qemu_co_mutex_lock(&s->lock);
if (ret < 0) {
--
2.26.2
- [PULL 12/22] qemu-img: Explicit number replaced by a constant, (continued)
- [PULL 12/22] qemu-img: Explicit number replaced by a constant, Max Reitz, 2020/09/15
- [PULL 09/22] qcow2: Fix removal of list members from BDRVQcow2State.cluster_allocs, Max Reitz, 2020/09/15
- [PULL 13/22] iotests: Skip test_stream_parallel in test 030 when doing "make check", Max Reitz, 2020/09/15
- [PULL 14/22] block/vhdx: Support vhdx image only with 512 bytes logical sector size, Max Reitz, 2020/09/15
- [PULL 15/22] qcow2: Handle QCowL2Meta on error in preallocate_co(), Max Reitz, 2020/09/15
- [PULL 16/22] qcow2: Make qcow2_free_any_clusters() free only one cluster, Max Reitz, 2020/09/15
- [PULL 17/22] qcow2: Return the original error code in qcow2_co_pwrite_zeroes(), Max Reitz, 2020/09/15
- [PULL 18/22] block/rbd: remove runtime_opts, Max Reitz, 2020/09/15
- [PULL 19/22] block/qcow: remove runtime opts, Max Reitz, 2020/09/15
- [PULL 22/22] block/rbd: add 'namespace' to qemu_rbd_strong_runtime_opts[], Max Reitz, 2020/09/15
- [PULL 21/22] qcow2: Convert qcow2_alloc_cluster_offset() into qcow2_alloc_host_offset(),
Max Reitz <=
- [PULL 20/22] qcow2: Make preallocate_co() resize the image to the correct size, Max Reitz, 2020/09/15
- Re: [PULL 00/22] Block patches, Peter Maydell, 2020/09/15